I think Nadal totally belongs here. I really, really hate him but sadly he is more than just a clay courter as people would like to believe.
Tsonga's name shouldn't even be up for consideration. A fluke run, even if it happens at a big event shouldn't be enough without something to back it up.

This is MTF sacrilege, but Roddick belongs on this list. You may hate him, and his results on clay are miserable, but there is no way he is NOT a top 5 hard court player at the moment.